Abstract

Saturation current methods have been used to measure ion‐production rates with and without the addition of a nonreactive quenching compound (N2O). These measurements strongly indicate that metastable molecules play a decisive role in chemi‐ionization processes occurring in atomic O and N systems. Mobilitymeasurements, derived from an analysis of transient currents resulting from pulsed operation of the ion‐collection system, identify the predominant ion as NO+. No change in this mobility occurs from 0.6 to 100 msec after a pulsed clearing field has removed ions previously created. This and other observations indicate that NO+ is the initial ion formed by chemi‐ionization processes. Only the reactions N+N+NO*→N2+NO++e and N2*+NO*→N2+NO++e are consistent with these observations.